1. Technical Field
The present invention relates to liquid ejecting apparatuses equipped with a piezoelectric element that includes electrodes and a piezoelectric layer to generate a change in pressure of a pressure generation chamber communicating with a nozzle opening.
2. Related Art
As a typical example of liquid ejecting heads mounted in liquid ejecting apparatuses, there is provided an ink jet recording head, for example, in which a part of a pressure generation chamber that communicates with a nozzle opening for discharging ink droplets is configured with a vibrating plate, and this vibrating plate is deformed by a piezoelectric element and pressurizes ink in the pressure generation chamber so as to discharge the link through the nozzle opening as an ink droplet.
As a piezoelectric element used in a liquid ejecting head, there is provided such an element that is configured by sandwiching a piezoelectric material which has an electromechanical conversion function, for example, a piezoelectric layer made of a crystallized dielectric material between two electrodes. Such piezoelectric element is mounted in a liquid ejecting head as a flexural vibration-mode actuator, for example. Note that, as a typical example of the liquid ejecting head, there exists an ink jet recording head, for example, in which a part of a pressure generation chamber that communicates with a nozzle opening for discharging ink droplets is configured with a vibrating plate, and this vibrating plate is deformed by the piezoelectric element and pressurizes ink in the pressure generation chamber so as to discharge the ink through the nozzle opening as an ink droplet.
A piezoelectric material that is used as a piezoelectric layer constituting such piezoelectric element is required to have an excellent piezoelectric characteristic, and as a typical piezoelectric material, lead zirconate titanate (PZT) can be cited. However, in view of an environmental problem, a piezoelectric material without containing lead or a piezoelectric material whose lead content is suppressed has been required. As a piezoelectric material without lead, for example, there exists a BiFeO3-based piezoelectric material containing Bi and Fe (for example, see JP-A-2007-287745).
However, because such a piezoelectric layer that is made of a complex oxide without lead or with a suppressed lead content does not provide a sufficient amount of displacement in comparison with lead zirconate titanate (PZT), an increase in the amount of displacement is needed.
Of course, not only the ink jet recording head, but also other types of liquid ejecting heads that discharge a liquid other than ink have the same problem; in addition, the same problem also occurs in piezoelectric elements that are used in other apparatuses than the liquid ejecting head.